Greenville firefighters in full gear stood by Friday afternoon as air safety investigators used a crane to lift a ruined jet that held a voice recorder in its belly.

The 1982 model Dassault Falcon 50, reeking of spilled fuel, had crashed the previous afternoon at Greenville Downtown Airport, killing its two pilots and seriously injuring two passengers. The reason for the accident remained unclear Friday, and investigators noted the clear weather and experienced pilots.

"I'm going to get the cockpit voice recorder out," said Dan Boggs, an air safety investigator with the National Transportation Safety Board. "We are going to put that on an aircraft headed to Washington, D.C., this afternoon and that will be downloaded in our laboratories."

His agency is investigating why the jet overshot the downtown airport's north-south runway at Thursday afternoon before touching down and sliding into grass alongside the runway, tumbling down a steep embankment and coming to rest against the airport's white fence along Airport Road.

A line of orange cones in the grass above the embankment showed the doomed jet's path.

“We all saw it land, and for some reason it did not stop," airport director Joe Frasher said.

Boggs said visibility was not an issue and the pilot radioed air traffic control minutes before the crash to say he could see the airport. The runway at Greenville Downtown Airport meets the needed length for the triple-engine plane that crashed Thursday, he added.

"It's fine," Boggs said of the runway. "This jet right here, that's a perfect runway."

Frasher made similar comments Thursday, also noting that larger planes land on the runway. The airport has no operational issues, and the FAA has made no safety recommendations, he said.

“The FAA strictly controls all airports. You’re at their mercy, so to speak," Frasher said. “I’m not aware of what caused this, but there’s no issue with the airport."

Frasher said the downtown airport might consider adding another "engineered materials arrestor" system, also known as an "EMAS," at the end of the south runway. That device works to stop an airplane that overshoots a runway, but it actually wouldn't have worked in this case, Frasher said, as the Falcon 50 aircraft slid off the side of the runway before it slid off the end.

"He wouldn't have hit the EMAS," Frasher said.

The Coroner's Office said the plane overshot the runway, with the fuselage breaking at the cabin after the jet crashed at the airport on Tower Drive.

Airport Road remained blocked to through traffic Friday evening, with Greenville police and fire vehicles blocking the way.

Boggs said voice recordings, air traffic control recordings from minutes before the crash, and surveillance video from nearby businesses will help provide answers to what happened. Investigators weren't sure whether the plane had a flight data recorder due to its age.

Boggs said the plane took off from Tampa, and Greenville was its final destination.

The Greenville County coroner has identified the pilot killed as John Christian Caswell, 49, of Port St. Lucie, Florida. He was pronounced dead about an hour after the crash occurred, the Coroner's Office said.

A woman who answered the door Friday afternoon at Caswell’s listed residence in central Port St. Lucie declined to speak.

Sylvia Lawson and her husband, Jerry, said they’ve lived next door to Caswell for three years.

They recalled how he allowed them to run a power line to his home after one of the recent hurricanes. The Lawsons said they couldn’t get their generator to start.

“He was a very kind gentleman. Very kind. Always pleasant to talk to,” Jerry Lawson said. “He was a good neighbor.”

Caswell's co-pilot, Stephen George Fox, of Indian Rocks, Florida, also died when the mid-sized jet tried to land at the airport but ran off the runway and split in two, causing a fuel leak that emergency crews rushed to contain.

NTSB investigators expect to remain at the site of the crash for three or four more days. Boggs said the plane will then be moved to a salvage site in Georgia where investigators will continue to have access to it over the next several months.

A preliminary report is expected in two to three weeks and a full factual report typically takes 12 to 18 months, according to Boggs.

Will Greenlee, a reporter for Treasure Coast Newspapers in Florida and part of the USA TODAY Network, contributed to this report.